The Core Story

By Lilly Roehrig, Guest Author, Graduate Student, Environment & Natural Resources, Department of Geography, University of Alabama  

From the moment I rumbled into the Paint Rock forest on an ATV, I was in awe of the thousands of shades of green that each tree contributed to the rippling mosaic of the forest. One might assume that the years and disturbance events those trees have survived are lost to the passage of time, but our crew knew better. There is a secret history to be discovered beneath Paint Rock’s broadleaf canopy, and that very day we were beginning our journey to uncover it.

As a University of Alabama graduate student researcher in Justin Hart’s Forest Dynamics Lab, I’ve had the opportunity to work on a variety of projects across Alabama and Tennessee that address pertinent forest management issues using science-based solutions, with a particular focus on forest stand dynamics and silviculture. Our work at Paint Rock in July of 2026 was one of these projects, fully funded by the Paint Rock Research Center (with a grant from the Tom Sardy Foundation).

Students from the University of Alabama gather at a plot center in the Paint Rock forest to review their tree cores. They include Alexandria Roberts (left), Lilly Roehrig (left center), Kana Furukawa (right center), and Lucille McGuire (right).

Our lab set out to core over a thousand trees in the 60-hectare Paint Rock forest dynamics plot to begin to build a story of their past. Kana Furukawa, my fellow graduate student researcher and leader of our fieldwork at Paint Rock, describes the project as a “…spatiotemporal analysis of canopy disturbances and tree establishment” that will “… add context to our understanding of the relationships between canopy disturbances and regeneration across spatial scales.”

By adding data to the pre-existing forest census dataset via tree ages and growth rates, we can reconstruct the establishment patterns of trees and identify canopy disturbance events, such as tornadoes or ice storms, that have influenced stand development and succession. Along with determining a tree’s age by dating the rings of a sample, we can also view other information, such as anomalous growth changes, that may indicate when and where the canopy was disturbed.

Together, these data allow us to reconstruct the forest’s history and identify patterns of disturbance and regeneration across time. This will help guide future conservation and management decisions, and the information can also support future ecological research at Paint Rock.

PhD student Lucy McGuire cores into an American beech tree.

However, before this history could be read, we had to collect the tree core samples from several species. By coring more than a thousand trees, we’re able to reconstruct disturbance patterns across the entire study area and glean a broader context of how different species and stands responded to disturbances through time.

With increment borers—which consist of three main components: the bit, the handle, and the spoon—we collected our samples. As we pressed the tip against the tree and turned the handle clockwise, the bit caught on the bark and began to burrow into the tree. While we continued to turn, the wooden core was carved out. Once we cored far enough into the tree to hit the pith (the “center” of the tree), we inserted the spoon and turned the borer counterclockwise to remove the bit. The spoon—a narrow, cup-shaped piece of metal—was slid inside the hollow bit, and when removed, it contained the core. We inserted the cores into a paper straw for transportation, labeled with its corresponding forest dynamics tree ID number.

A student pulls the spoon out of the bit, which contains the tree core sample.

Tree cores can range anywhere from a few centimeters to several decimeters or longer, depending on the tree diameter, but the process does not harm the tree. Many trees have the ability to quickly respond to small wounds such as those that coring causes, which are only a few millimeters in diameter, and long-term studies have shown that coring does not significantly impact tree mortality.  

As we worked, I learned that tree coring is as much an art as it is a science. Feeling the tethering bite of the bit as it catches into the smooth bark of a maple or knowing when to pull out of an oak with a rotten center were skills that took me many field days to master. As a crew, we grew faster, stronger, and more efficient at our tasks as time went on, and soon the creaking of a borer carving through wood became music to my ears.

Above: University of Alabama student Alexandria Roberts uses a microscope to count rings on a tree core, which is a part of the dating process. Below: Tree cores that the University of Alabama students have collected, mounted, and sanded.

After a month of fieldwork at Paint Rock, we finally collected the last sample and returned to Tuscaloosa to begin processing. In the lab, we mount the tree cores with their cells vertically aligned and glued to a piece of routed wood, and then we sand the samples with abrasives at various levels to reveal the individual tree-ring structure. Once sanded, each tree-ring series is examined under magnification.

Kana and other students in the Forest Dynamics Lab date the annual rings to the calendar year of formation, identify scars or growth releases associated with disturbances using statistical techniques, and compile the information into geo-referenced datasets that can be analyzed alongside Paint Rock’s existing forest census records.

This is a long process, and one that is still ongoing. Though there is still much work to be done, I feel proud that through our research, we will be able to better understand the disturbance and developmental history of a Southeastern hardwood forest, which ultimately may improve the ability to manage it. Additionally, I am excited to see what further research will reveal about the extraordinary ecosystem at Paint Rock.

Roads to New Partners

By Bill Finch, Founding Director

There’s an arbitrary and misleading line standing between the Paint Rock Research Center and Sewanee, the University of the South.

Sewanee is not much more than 50 minutes up the road from our upper campus here in the valley. Except for a couple of monster hills, it’s not a bad bicycle ride. But on the way there’s a sudden transition from loud red elephants to big orange T’s, and that pointless line dividing one state from another makes us seem much further apart than we are.

The Greater Paint Rock ecosystem we recognize always included Sewanee and lands a little north of there. The increasingly famous pre-Columbian artwork illuminated by Sewanee and University of Tennessee researchers is as rich south of the state line as it is northward. Every year, new research reinforces those ties. The new trees and plants we discover in Paint Rock wander freely up to Sewanee and the University’s 13,000-acre Domain. Underground rivers carry life under mountains, moving sightless cavefish from one side of the border to the other. Sewanee’s Kristen Cecala notes that significant changes in salamander genetics north and south of Interstate 24 lasso Sewanee and Paint Rock into a common ecosystem.

A view of the forest that unites us.

Now, the two campuses seem ready to converge in a new relationship that will bring benefits to both. We explored the possibilities around Sewanee’s campus early this summer, and a big contingent of Sewanee faculty visited Paint Rock a couple of weeks ago. A forestry class from Sewanee is scheduled for their first visit next week. And Sewanee convened a meeting with the Appalachian Conservation Institute, a non-profit preserving large landscapes surrounding the Little Sequatchee River, multiplying opportunities along this extraordinary highway of biodiversity in the Southern Cumberlands.

The Research Center has always worked to be a resource for all researchers, and all universities. Sewanee is just one of our partners. We have long and exciting relationships with University of Alabama, Alabama A&M, Jacksonville State University, Auburn, University of West Alabama, and research institutions like HudsonAlpha. We work closely with University of Georgia, and researchers come here from as far away as New England and California. Sewanee isn’t a Tier 1 research institution like some of those. But it’s a place where students have a unique opportunity to engage with the natural world, and the school’s liberal arts curriculum has a revered reputation for turning out leaders in many fields.

From top-left to bottom: Researchers from Sewanee and Appalachian Conservation Institute tour the Paint Rock forest; Sewanee forest research and education biologist Christy Soldo looks out on our prairie restoration work at Hellums Research Outpost; Sewanee aquatic biologist Kristen Cecala inspects a crayfish at our Big Ellum Bottom Research Outpost on the Paint Rock River.

What makes our growing relationship with Sewanee distinctive is our mutual recognition that there’s something important going on here at the southern end of the Cumberland Plateau. It’s not some Brigadoon-like retreat from the world—it really is a storehouse of biodiversity that’s always played an exceptional role in the life of North America, and must again. We agree it’s our job to understand it, look after it, and share its riches with a new generation. We’re looking at programs that unite us in research and restoration, conservation and communications.

You’ll soon hear more about our plans with Sewanee.